Study On Seismic Behavior Of Deep Beam Infilled Steel Frame Under Horizontal Earthquake Action

Shear walls and steel frame are two commonly used system for building structure. Most of reinforced concrete shear wall is brittle failure and difficult to repair after the earthquake; Lateral stiffness of steel frame is small,so it easily lead to the destruction of nonstructural members. Therefore, it is limited in high earthquake fortification zone. In order to realize the modulation of structural stiffness in a certain range, Deep Beam can be as a new anti-lateral force member or the strenghening member. It can be widely used in the new building, and strenghening or renovation building. Based on the model test, calculation analysis and push-over analysis, seismic behavior of the structure was studied.The main content is described as follows:1. According to model test of pure steel frame, steel plate deep beam infilled steel frame (SDBF), reinforced concrete deep beam infilled steel frame (RDBF) and composite steel and concrete deep beam infilled steel frame (CDBF) under horizontal load, deformation, hysteresis curves and so on of these structure were analyzed.These results showed that: The hysteresis loops of the tests are replete;deep beam can be used as the first defence line of earthquake-resistance and the steel frame can be used as the second;by changing span-height ratio, the initial stiffness of the structure can be ajusted within a certain range; reinforced concrete deep beam is the most prominent in raising the initial stiffness; energy dissipation of composite steel and concrete is best.Finally, the failure mechanism of the deep beams were investigated.The thesis suggested that elastic angular displacement limited value is 1/300 and plastic angular displacement limited value is 1/40 of SDBF and CDBF; elastic angular displacement limited value is 1/550 and plastic angular displacement limited value is 1/50 of RDBF.2. The deep beam and steel frame composed of hybrid structural system to stressing under the external load. In order to analyse load distribution of the deep beam and the steel frame,the hybrid structural system can be simplified as a caulation model.The steel deep beam is simplified as:two opposite edges with load clamped and the other two without load free.Analyzing the critical stress of the beam under non-uniform pressed status with the energy method.Making the post-buckling strength as ultimate limit state to analyze the effective height after the bending of the steel deep beam.3. According to hysteresis loops of the tests, the thesis suggested restoring force mode of RDBF,SDBF and CDBF under horizontal load. The thesis also gave the stiffness calculative formulas of exponential and hysteresis curves.4. Finite element model of RDBF was established by the SAP2000 software to make push-over analysis and verify the feasibility.At the same time, one layer or two layers model of full-scale steel frames were established to analyze the structure performance with reinforced concrete deep beam.